1. Field of the Invention
This invention relates to a wood preservative composition and, more specifically, it relates to a wood preservative composition comprising an alkyl ammonium compound as an active ingredient and a polyacid salt having dispersing effect as an auxiliary ingredient.
2. Description of the Prior Art
Wood is one of very important resources as material for telegraph or electric light poles and constructional members such as substrates and posts of houses, as well as for chips as the starting material of paper and pulp. However, since such important wood tends to be rotten by the attack of various types of wood rotting blacket fungi, complete preservation treatment has to be applied so that the wood may not be rotten by the invasion of these fungi. Particularly, since the wood for use in the constructional members are often used during as long as from ten and several years to several decades and wood preservative agents have to possess their effect for a long period in the wood, high stability and low volatility are required for the preservative agents.
For the above requirement, wood preservative agents comprising various types of organic or inorganic compounds as the effective preservative ingredient have hitherto been proposed and used widely.
These wood preservative agents are injected into the wood for applying preservation treatment in various ways such as by pressurized injection, immersion and coating, and the use of a water-soluble wood preservative agent is suited for the pressurized injection. Inorganic preservative agents of copper-chromium-arsenic system (hereinafter simply referred to as CCA) have been used practically at present for the pressurized injection.
However, the CCA preservative agents are much defective in view of the health and sanitation or prevention of circumferential pollutions as below. Specifically, (1) since the CCA system contains those heavy metals extremely toxic to human bodies such as chromium and arsenic, a very strict health-keeping management has to be taken for workers in the step of preservation treatment and a great care has to be paid in the disposal of the treating agent as well, and (2) the CCA system comprises a mixture of heavy metals whose natural resorces have been decreased and restricted.
In view of the above situation, development of less toxic water-soluble preservative agents has been demanded world-wide in place of the toxic CCA preservative agents and general attention has now been directed to alkyl ammonium compounds which are widely utilized in ordinary fungicides as such water-soluble wood preservative agents (hereinafter sometimes referred to as AAC).
The utility of the AAC system as the water-soluble wood preservative agent has gradually been recognized world-wide in recent years in that they have very much excellent performances in the antibacterial effect against the wood rotting bracket fungi, adhesion to the wood, injection into the wood and less toxicity as well. However, the use of the AAC preservative agent to the materials has been hesitated in the case where they are berried in the ground or used under water since it is somewhat inferior to the CCA preservative agent in view of the anchoring property to the wood for a long period.